Midpoint Formula
M ((x1+x2)/2, (y1+y2)/2)
If two figures are congruent, these are also congruent
Corresponding sides and corresponding angles
The addition of two interior angles of a triangle
The measure of the exterior angle opposite to them
Reflect (1, - 3) across the y axis
(1,3)
A statement that you can prove using a series of logical steps
Theroem
If segments a and b are congruent, and segments b and c are also congruent, then segments a and c are congruent.
Transitive property of congruence
An alternate way to prove triangle congruence, only for right triangles
hypothenuse leg theorem of congruence (HL)
These triangles have a pair of congruent sides and congruent inside angles
Isosceles triangles
Two interior angles of a triangle measure 40° and 60°, then the measure of the exterior angle opposite to them is
80°
A rigid motion exists that maps the figure onto itself.
Symmetry
Nonadjacent angles that lie on opposite sides of the transversal between intersected lines.
Alternate interior angles
Triangles are congruent by these theorems
corresponding parts of congruent triangles are congruent (CPCTC)
angle side angle (ASA)
side angle side (SAS)
side side side (SSS)
angle angle side (AAS)
hypothenuse leg (HL, right triangles only)
Point located 2/3 of the distance from each vertex to the midpoint of the opposite side
Two parallel lines, m and n, are intersected by a transversal, t. Angle A = 105° is located in the inside of the cut between t and m and n, what is the value of the same-side interior angle of A?
75°
What type of rotation is (x,y) -> (-x, -y)
180° rotation
If a point is on the ___________ of a segment, then it is equidistant from the endpoints of the segment.
The congruency of the three inside angles in two triangles is not enough to prove their congruence
The sides can be extended or shortened, making them not congruent.
Triangle midsegment theorem
The segment joining the midpoints of two sides of a triangle is parallel to the third side, and its length is half the length of that side
Find all midpoints of the triangle ABC with endpoints A(-7,-1), B(-5,5) and (1,3)
midpoint AB = (-6,2)
midpoint AC = (-3,1)
midpoint BC = (-2,4)